Management Detail

Strawberry crown moth

Strawberry crown moth is primarily a pest in southern Washington and Oregon. Adults are clear winged moths that resemble yellow jackets and fly in June and July. They lay eggs on the undersides of leaves near the crown of the strawberry plant. The larvae then hatch out and feed on the inside and outside of strawberry crowns causing plant stunting and subsequent yield reduction. Severe feeding can cause plant death. Larvae are white with a brown head and approximately one inch long and overwinter in strawberry crowns and roots.

Examine weak plants in the field in the spring and weak plants that prematurely redden in the fall for the presence of SCM larvae.

Infested plants usually break off at the crown when gently pulled, revealing tunneling that is filled with rust colored frass.

Once larvae are established in the plant crown, there are no adequate control strategies so all insecticide control strategies target newly hatched larvae and adults, which, are present June-July.

A very effective pheromone is widely available. Sticky traps should be put out close to ground level in early June.

Correct insecticide timing is essential. The first application needs to be made about the time the eggs begin to hatch, a second application should be made 10 to 14 days later and (often) a third 14 days later.

The first application is timed by the pheromone trap counts. Go on 10-14 days after 2 or more adults are caught for 2 days in a row.

Cultural Controls:

Topping plants immediately after harvest but leaving some untopped will force emerging adults to lay eggs on untopped plants. These can then be tilled under.

Infested plants redden prematurely in the fall and can then be removed.